Cam control assembly



June 19, 1962 MlYOSHl MORI 3,039,323

CAM CONTROL ASSEMBLY Filed July 15, 1959 2 Sheets-Sheet l June 19, 1962MlYOSHl MORI CAM CONTROL ASSEMBLY 2 Sheets-Sheet 2 Filed July 15, 1959United States Patent 3,039,323 CAM CONTROL ASSEMBLY Miyoshi Mori, 40Ganjiyama, Ohn, Japan Filed July 15, 1959, Ser. No. 827,378 Claimspricrity, application Japan Get. 15, 1958 4 Claims. (Cl. 74568) Thisinvention relates to a zigzag sewing machine, and has for its object toprovide a zigzag sewing machine equipped with an improved pattern camassembly con sisting of a plurality of superposed cams for controllingthe zigzag swing motion mechanism, and in which the configuration of thecombined controlling cam may readi 1y be varied for any selected one ofthe stitch patterns without detaching or changing any of the camelements.

Another object is to provide a simple, practical and reliablearrangement for accomplishing the foregoing.

According to this invention, the zigzag sewing machine comprises aneedle bar supported by swing arms, a zigzag swing motion mechanismdriven from an upper shaft of the machine and having a cam follower, anda controlling cam assembly engaging with said cam follower, which camassembly consists of a plurality of superposed plate cams mounted on acam shaft, such as a basic cam disc, a main cam disc radially shiftablerelative to said basic cam disc, and an auxiliary cam or cams so mountedon a supporting disc to be rotatable on an axis parallel to said camshaft according to rotation of said cam shaft, thereby to vary thecombined outer configuration of the controlling cam assembly.

The accompanying drawing will serve to illustrate a specific embodimentof my invention, in order that its utility and functioning Will bethoroughly appreciated. It will be understood, however, that this is byway of illustration only and is not to be taken as limiting theinvention in any Way.

In the accompanying drawings:

FIGURE 1 is a perspective view of the driving mechanism of the zigzagsewing machine equipped with the controlling cam constructed accordingto this invention;

FIGURE 2 is a section taken along line II-II of FIGURE 1;

FIGURE 3 is an end view of FIGURE 2 as seen in the direction of arrow A;

FIGURE 4 is an exploded perspective view of the controlling cam assemblyshown in FIGURE 2;

FIGURE 5 is a cross section showing the oneway driving connection of thecontrolling cam mechanism;

FIGURE 6 is a similar section showing the oneway driving connection ofthe dial control;

FIGURE 7 is a diagrammatic view showing the outer configuration of thecontrol cam as set for straight stitching; and

FIGURE 8 is a similar view showing one example of change of the outerconfiguration of the controlling cam adjusted for zigzag stitching.

Referring to FIGURE 1, the reference numeral 1 designates the uppershaft of the sewing machine. This shaft 1 drives a triangular cam 4through worm gears 2 and 3 at a reduction ratio of 1/2. A vertical shaft5 fixed to the machine frame carries an adjusting arm 6, to which ispivotally mounted a forked arm 7. Said arm 7 is provided on its uppersurface with a curved slot and on its lower surface with a straightslot. The triangular cam 4 engages with said straight slot and,according to rotation of the cam 4, the forked arm 7 is oscillated in ahorizontal plane. Said triangular cam 4 is so shaped that the forked arm7 is stopped at interval for a predetermined period of time. Engagedwith the upper curved slot of the arm 7 is a square block 8 on the freeend of a driving link 9 which is pivotally connected to the free end ofan arm 11 fixed to a vertical shaft 10. The square block 8 carries aroller (not shown) which is engaged by a slot formed at the free end ofa zigzag width adjusting arm 12, whereby the motion of the free end ofthe driving link 9 is limited. To said link 9 is connected a bracket 13which carries a connecting rod 14 for oscillating swingable arms 15supporting a needle bar 16 and a needle 17. By the oscillating motion ofthe forked arm 7 according to the rotation of the triangular cam 4, thearm 11 is oscillated through the link 9, so that the swing arm 15 isoscillated through the bracket 13 and the connecting rod 14. Similaroscillating motion is transmitted to the shuttle 20 through a connectingrod 18 and an arm 19. A bevel gear 21 is engaged with the root of thezigzag width adjusting arm 12 and is in mesh with another bevel gear 22.The latter is fixed on a shaft for manual adjustment of the width of thezigzag stitch. A worm 23 is fixed on the upper shaft 1 and meshes with aworm wheel 24 which has a suitable reduction gear ratio. A controllingcam assembly is generally designated by the numeral 25. A cam follower26 having the height equal to the whole thickness of the assembled camsand supported by arms 27 and 28 is normally held pressed against theouter peripheral face of the cam assembly by means of a spring (notshown). Said arms 27 and 28 are secured to a vertical shaft 29. Thisshaft 29 is loosely mounted to a switching frame 30 which is in turnloosely mounted on pin 31 fixed to the machine frame. The frame 30 isprovided with an operating handle 32 which is actuated when necessary topull the follower 26 out of engagement with the cam assembly 25 when itis desired to change the cam configuration. A fork ended link 33 isconnected at one end to the upper end of the shaft 29 and at the otherend to the arm 12. By this connection the motion derived from change ofthe configuration of the cam assembly 25 is transmitted to the zigzagwidth adjusting arm 12 through the follower 26, arms 27, 28 and theshaft 2?.

According to this invention, in order to fulfil the above mentionedobjects, the cam assembly 25 is constructed and arranged as follows:

Referring to FIGURES 2 and 4, the worm wheel 24 which is in mesh withthe worm 23 rotating with the upper shaft 1 is loosely mounted on ashaft 37 securely mounted on the machine frame 35 by means of a setscrew 36, and is provided with pins 38 secured thereto for drivingconnection of a cam supporting disc 39. This disc 39 has a boss providedwith holes 40 for engagement with said pins 38 on the worm wheel 24. Thedisc 39 has on the other end an integral stud 41 which is inserted intoa central bore 43 formed in a cam shaft 42. This shaft has on its innerend a main or sun gear 45, and the outer endis journalled in the machineframe. Meshing with said main gear 45, there are four planetary pinions46, 46' having secured thereto four auxiliary earns 47, 47' .which havespeed increasing gear ratio of 2:1. While four pinions and fourauxiliary cams are shown by way of example, it is to be noted that theinvention is not limited to the number of the pinions and cams.superposed upon said auxiliary cams 47, 47 there is a circular basic cam48 mounted on the cam shaft 42 and connected to the supporting disc 39by means of studs 49, 49 and nuts i), 50" the basic cam 48 having samediameter as that of the supporting disc 39 and being fixed relative toeach other with respect to rotation. The pinions 46 and auxiliary cams47 are arranged around the cam shaft and are respectively rotatablearound said studs 49 by rotation of the main gear 45. Radius ofcurvature R (FIG. 4) is made equal to the radius of curvature ofperiphery of each of the supporting disc 39 and the basic cam disc 48.This basic cam disc 48 has a central bore S1 receiving the cam shaft 42.The inner wall of said bore is provided with a gradually enlargingrecess 52, into which are inserted a spring 53 and a ball 54 as shown inFIGURE 5. By such arrangement, when the basic cam disc 43 is rotated inthe counterclockwise direction as seen in FIGS. 4 and 5 the cam shaft 42is also rotated in the same direction, whilst when the disc 48 isrotated in the reverse direction the cam shaft 42 is never rotated andremains stationary. The basic cam disc 48 has a pin 55. A main cam disc58 superposed upon the said basic cam disc 48' has a radially arrangedoblong slot 56 engaging with said pin 55, and there is a circular bore57 of which center is eccentric to the outer diameter, the eccentricitybeing shown by L. A main cam guide disc 60 which has a circular boss 5%engaging with said circular bore 57 of the main cam disc 58. The camshaft 42' is inserted through the central bore of the guide disc 60, andthe latter is secured thereto by means of a set screw 61. The outerdiarneter of the main cam disc 58 is equal to the outer diameter of eachof the cam supporting disc 39 and the basic cam disc 48. The outerperiphery of the main cam guide disc 60 is concentric with the centralbore thereof, whilst the center of the circular boss 59 is eccentric tothe center of the central bore. A leaf spring 62 prevents the axialvibration of the cam shaft 42. An indicator disc 63 is secured to saidcam shaft 42 and bears the stitch pattern marks. An adjusting knob 64 isconnected to the cam shaft 42 in such manner that oneway rotation onlyis transmitted to the cam shaft 42, as by means of a oneway drivingconnection including a spring 65 and a ball 66 (see FIG. 6), which aresimilar to those shown and described with reference to FIGURE 5. Saidadjusting knob 64 is prevented from being detached from the cam shaft 42by means of a cover ring 68 made of transparent plastic material whichis secured to the machine frame by set screws 67.

The operation of this invention is as follows: The rotation of the wormgear 24 which is driven from the worm 23 on the upper shaft 1 at apredetermined reduction ratio is transmitted to the cam assembly 25consisting of the auxiliary cams 47, 47 the basic cam disc 48, and themain cam disc 58, in unison, through the cam supporting disc 39. Uponthe rotation of said cam assembly, the motion of the follower 26engaging with the peripheries thereof will be transmitted to the zigzagstitch swing motion mechanism as hereinbefore described with referenceto FIGURE 1. Now, when the knob 64 is rotated in the direction of arrowin FIGURE 6, the cam shaft 42 is rotated, whereby the eccentric main camdisc 58 guided by the eccentric boss 59 of the guide disc 60 on theshaft will be radially shifted along the pin-andslot connection 5556-,bringing a phase displacement. At the same time, the pinions 46-, 46meshing with the main gear 45 on the shaft 42 and carrying the auxiliarycams 47, 47' will perform a planetary motion like movement relative tothe shaft 4 2, each pinion rotating on its own axis 49.

Referring to FIGURE 4, the radius of curvature R of the auxiliary cam 46(and R of 46) is made equal to the radius of the peripheral circle ofeach of the cam supporting disc 69, the basic cam disc 48 and the maincam disc 58, whilst the remaining peripheral face of the auxiliary cam46 (46') has smaller radius of curvature B (B), and said larger radiusof curvature and the smaller radius of curvature are arranged in suchrelation that the dimension B is larger than b relative to the center ofthe pinion 46, as shown in FIGURE 4. By such arrangement, according topartial rotation of the knob 64, the combined cam face configuration ofthe main cam disc 58 and the cams 47 (47' may be brought into exactcoincidence with the configuration of the basic cam disc 48 as shown inFIGURE 7, and it may also be possible to make substantially indefinitenumber of changes of combined cam configuration by the manual operationof the said adjusting knob 64 through the radial displacement of themain cam disc 58 and by individual rotation of the auxiliary earns 47(47 When the combined cam configuration is in coincidence with the basiccam disc 48 which is a true circle as shown in FiG-URE 7, it will beobvious that the straight stitch may be obtained. On the other hand, asseen from FIG- URE 8 by way of example, when the phases of the main camdisc 58 and of the auxiliary cams are displaced relative to the basiccam disc 48, desired zigzag stitch may be obtained as shown at thebottom of FIGURE 8, the pattern of zigzag stitch being variable for widerange according to the variable configuration of the combined cams whichare determined by angular position of the adjusting knob 64. The stitchpatterns determined by various configurations of the combined cams areindicated on the indicator disc 63. During the operation of the machine,the cam assembly together with the cam shaft 42 and the said indicatordisc 63 secured thereto are rotated in unison in the direction of arrowin FIG- URE 5, but the adjusting knob 64 remains stationary by reason ofthe free wheeling connection as shown in FIGURE 6.

For changing the stitch pattern by displacement of the combined camelements, keeping the machine stationary, the adjusting knob 64 ismanually rotated to bring the selected one of the stitch pattern markson the indicator disc 63 into register with the index mark 6-9 on thetransparent cover ring 68. It will thus be seen that according to thisinvention the cam assembly may readily be adjusted and set to theposition allotted for the selected one of the stitch patterns.

Whatl claim is:

1. A controlling cam assembly comprising: a supporting shaft means forrigid mounting at a preselected place of carn assembly operation; a camsupporting disc mounted for rotation on said supporting shaft, a camshaft, having an integral main gear at one end, rotatably supported andaxially attached at the gear and by said cam supporting disc, said camshaft being journalled at the other end for radial support; a pluralityof planetary gears adapted to mesh with. saidmain gear for simultaneousrotation thereby; a plurality of annular auxiliary cams having similarperipheral cam surfaces, each said auxiliary cam being rigidly attachedto an end of a planetary gear and having portions of the peripheral camsurface with different radii of curvature, a basic cam disc havingapproximately the same diameter and peripheral cam surface as thesupport cam disc and defining a center hole for engaging said camsupport disc on the cam shaft, a plurality of spacing and securing meansrigidly spacing and securing the basic cam disc to the supporting camdisc for rotation about the cam shaft, and respectively securingtherebetween the planetary gears and attached annular auxiliary cams forrotation about said respective spacing and securing means, said gearsand attached auxiliary cams being radially and circumferentially spacedapart equally by said spacing means and positioned with respect to thesupporting and basic cam discs for at least one portion of theperipheral cam surface of each annular auxiliary cam to extend beyondthe peripheries of said support and basic cam discs, whereby theauxiliary cams are rotatable with the supporting and the basic cam discsaround the cam shaft and each auxiliary cam is rotatable around itsspacing and securing means by the rotation of said cam shaft andintegral main gear and planetary gears for adjustment of the peripheralcam surfaces of said auxiliary cams with respect to the peripheral camsurfaces of the supporting and basic cam discs.

2. A controlling cam assembly as recited in claim 1, wherein anadjusting knob is mounted on the outer end of the cam shaft through aoneway driving connection.

3. A controlling cam assembly as recited in claim 1, wherein a portionof the peripheral cam surface of each of the auxiliary cams has theradius of curvature equal to that of the basic cam disc.

4. A controlling cam assembly as recited in claim 1, wherein the basiccam disc is mounted on the cam shaft through a oneway drivingconnection, an eccentric pin mounted on said basic cam disc parallelwith said cam 6 shaft, and a main cam disc defining a radial slot and aneccentric outer bore adapted to allow the free passage of said cam shaftis superposed upon said basic cam disc, said eccentric pin engaging insaid radial slot to connect said main cam disc in radially shiftablerotation relative to the'basic cam disc.

References Cited in the file of this patent UNITED STATES PATENTS1,141,504- Street June 1, 1915 1,145,337 Street July 6, 1915 1,460,651Hall July 3, 1923 2,250,696 Avis July 29, 1941 2,594,911 Goff Apr. 29,1952 2,900,837 Brandt Aug. 25, 1959 2,900,937 Gegauf Aug. 25, 19592,903,528 Kuhn Sept. 8, 1959

